Asymmetrical stress generated by the erythrocyte lipid flippase triggers multiple bud formation on the surface of spherical giant liposomes.

Proteo-giant liposomes were electroformed from a mixture of lecithin vesicles and inside-out vesicles from erythrocytes. After addition of Mg-ATP in the vicinity of the proteo-giant liposomes, small buds appeared on the liposome surfaces, which--via an increase in lipids in the outer monolayer--demonstrated the active transport of lipids from the inner to the outer monolayer, indicating flippase activity.